In communities along the Yukon River, fishermen eagerly await the arrival of Chinook (king) salmon as they gear up for another fishing season.
The start of the first run of Chinook salmon can vary by as much as 20 days, depending on spring conditions. Over the past 50 years the first pulse of Chinook on the Yukon delta has occurred between June 6 and 26.
For Alaskans eager to begin fishing, 20 days can be a long time to wait to find out when the fish are actually coming and if their numbers will be large enough to support a harvest.
Traditional knowledge on the Yukon holds that spring weather conditions, including ice, temperatures, and wind determine when the fish enter the river, but each spring brings a different combination of conditions, so predicting the arrival of the first run can be tricky.
Researchers from NOAA Fisheries and the Alaska Department of Fish and Game, with the support of the Alaska Ocean Observing System, have identified several conditions that appear to be related to the timing of the Yukon River Chinook salmon run:
* Percentage of spring ice cover between St. Lawrence Island and the Yukon delta
* April air temperatures in Nome
* Marine surface temperatures just offshore of the Yukon delta in May
Using data from these spring conditions, researchers have predicted the timing of the first Yukon River Chinook run for the past two years within three days of the actual start of each run.
The forecast for 2012 is for a late run similar to that experienced in the cool spring of 2010. As of June 6, 2012 no kings had been caught in the test nets, so this year’s run may be a little later than in 2010.
For the latest run timing information and more information on the forecast visit the AOOS website (www.aoos.org).
source: NOAA Fisheries (www.afsc.noaa.gov)